England wicketkeeper Jos Buttler has been disappointed with his own form and backed "fantastic" out-of-form opener Adam Lyth.

The hosts, who have clinched the Ashes, are set to lose the fifth Test at The Oval after slipping to 206-3 in the second innings – still trailing Australia by 129 runs.

Buttler is unbeaten on 33 – his highest score of the series – heading into day four, while Lyth fell for 10.

Lyth (115 runs at 12.77) and Buttler (113 at 16.14) have both struggled to contribute to England's Ashes success with the bat.

"Yeah, I've had a really poor series, there's no real getting away from that. I've been very disappointed with my own form," Buttler said.

"But today I think was about just trying to scrap and stay in there. I wouldn't say I feel very good at the crease, but I'll try and show that fight and get in there, not playing my natural ways looking to attack but try and occupy the crease.

"If I'm going to be successful at Test cricket then I've got to do that and hopefully I've shown that I can do that a little bit tonight and then carry on again tomorrow."

Buttler said Lyth was also unhappy with his own form, but the wicketkeeper believes the opener is a talent.

"He [Lyth] is obviously disappointed but in the dressing room everyone knows what a good player he is," he said.

"Opening the batting is probably the toughest job and he's had two very tough sides to do that against.

"But everyone knows he is a fantastic player and he wouldn't be opening the batting for England if he wasn't.

"And just like myself, he'll be disappointed with the runs tally at the end of the day but it doesn't take away that he's still a fantastic player."